Renewable energy is currently used in the transport sector in the form of liquid and gaseous biofuels—mainly for light- and heavy-duty road vehicles—and in the form of electricity for trains, light rails, trams, and both two- and four-wheeled electric vehicles (EVs).
Liquid biofuels—primarily ethanol and biodiesel (including FAME and HVOi)—account for the largest share of transport fuels derived from renewable energy sources. They meet about 3% of total road-transport fuel demand, and around 2.3% of final liquid fuel demand (and a very small but growing portion of aviation fuels).112 In some countries in Europe, as well as in Brazil and the United States, they represent considerably higher shares.113
The growth of liquid biofuels has been mixed in recent years. Global biofuel production increased again in 2013, after a temporary lull.114 Concerns about using only environmentally and socially sustainable supplies are constraining the rate of growth in some regions. (See Bioenergy section.)
Limited but growing quantities of gaseous biofuels (mainly biomethane, which is purified biogas) are fuelling cars, buses, and other vehicles in several EU countries (most notably Germany and Sweden), and insome communities in China, North America, and elsewhere.115 By late 2013, there were almost 700 vehicle filling stations in Europe offering compressed biogas (CBG) blended with natural gas, and nearly 300 stations selling 100% CBG.116 Plans are under way in other regions, including the Middle East and Asia, to develop facilities for biomethane production and vehicle fuelling.117
Electricity is already commonly used to power trains, city transit systems, and an increasing number of electric vehicles including cars, buses, cycles, scooters, and motor bikes.118 A growing number of initiatives aim to link these transport systems with renewable electricity. Several German cities—including Frankfurt and Nuremberg—rely on renewable electricity to operate their light-rail and subway services, while the German state of Saarland was the first to switch its local rail services to 100% renewable electricity.119 Bogota, Colombia, rolled out South America's largest all-electric taxi fleet in 2013 and announced plans for a police fleet of 100 electric motorcycles.120
Although electric vehicles and plug-in hybrids (PHEVs) still represent a tiny share of overall automobile markets, they are making a strong entry in several countries, such as Norway where as of early 2014, more EVs than conventional vehicles were sold each month.121 In the United States, more than 8,000 electric charging stations were operating by the end of 2013.122 Many towns with 100% renewable energy goals have adopted EVs as part of their energy plans.123 Sweden aims for a fossil fuel-free vehicle fleet by 2030, with road vehicles powered primarily by biofuels or electricity, and the promotion of walking, cycling, and public transport as a further step towards Sweden's vision for an energy supply system with zero net atmospheric greenhouse gas emissions by 2050.124 In addition, hybrid transportation options also are emerging, such as electric-diesel and biodiesel-natural gas buses.125
Many of these developments, along with rapid advances in related technologies, are increasing the role of electricity in the transport sector and raising the possibility to use vehicle batteries to store power in support of variable renewables in future "smart-grids."126
i - Fatty acid methyl ester (FAME) and hydro-treated vegetable oil (HVO). See Glossary for more information.
112 Estimate of 3% from IEA, World Energy Outlook 2013, op. cit. note 1, p. 24; 2.3%from IEA, Tracking Clean Energy Progress, op. cit. note 42, p. 90.
114 F.O. Licht, "Fuel Ethanol: World Production, by Country (1000 cubic metres)," 2014, and F.O. Licht, "Biodiesel: World Production, by Country (1000 t)," 2014, used with permission from F.O. Licht/Licht Interactive Data, provided by Helena Chum, U.S. National Renewable Energy Laboratory (NREL), personal communication with REN21, 4 March, 2014.
115 See, for example, "Arla Brings Milk Minus Emissions to UK," ngvglobal.com, 19 February 2014, http://www.ngvglobal.com/arla-brings-milk-minus-emissions-to-uk-0219#more-30327; "Oslo Buses to be Fueled by Liquefied Biomethane," ngvglobal.com, 12 February 2014, http://www.ngvglobal.com/oslo-buses-to-be-fueled-by-liquefied-biomethane-0212#more-30213; "Berlin's Household Waste Fuels Refuse Fleet," ngvglobal.com, 18 January 2014, http://www.ngvglobal.com/berlins-household-waste-fuels-refuse-fleet-0118#more-29935; "Bus Depot Largest Biomethane Refueller in Gothenburg," ngvglobal.com, 28 September 2013, http://www.ngvglobal.com/bus-depot-largest-biomethane-refueller-in-gothenburg-0928#more-28659; Switzerland from Dunja Hoffmann, Deutsche Gesellschaft für Internationale Zusammenarbeit(GIZ), personal communication with REN21, 29 April 2011; "After Completion of the Province to Start the Car Biogas Project Nissan Car 30,000 cubic meters of biogas," Hainan Shenzhou New Energy Construction & Development Co., Ltd, 14 October 2013, http://www.hainanbiogas.com/page.php?xuh=37 (using Google Translate); "The Morale of the Shortage' Hainan's First Car Started to Crack in Sight Biogas Plant," Hainan Shenzhou New Energy Construction & Development Co., Ltd, 14 October 2013, http://www.hainanbiogas.com/page.php?xuh=32 (using Google Translate).
116 Vehicle stations from "European Biomethane Filling Station Mapping Begins with Finland," ngvglobal.com, 30 November 2013, http://www.ngvglobal.com/european-biomethane-filling-station-mapping-begins-with-finland-1130#more-29417. In Germany, for example, as overall road vehicle sales declined, sales of natural gas vehicles rose almost 40% (to 4,300 vehicles) in the first half of 2013, relative to the same period in 2012 (3,100 vehicles), from "Germany's NGV Population Grows at Record Pace," ngvglobal. com, 23 July 2013, http://www.ngvglobal.com/germanys-ngv-population-grows-at-record-pace-0723#more-27863. See also "Biomethane Fuel Gains Ground in Germany," ngvglobal.com, 31 March 2013, http://www.ngvglobal.com/biomethane-fuel-gains-ground-in-germany-0331#more-26326.
117 Forexample, "Distiller Methane to Power Vehicles in Philippines," ngvglobal.com, 2 December 2013, http://www.ngvglobal.com/distiller-methane-to-power-vehicles-in-philippines-1202#more-29433; "Waste Management Builds New Biomethane Facilityfor Fleet Refueling," ngvglobal.com, 18 October 2013, http://www.ngvglobal.com/waste-management-builds-new-biomethane-facility-for-fleet-refueling-1018#more-28867; "ENOC and Dubai Sign MoU to Convert Flared Biogas to Biomethane Fuels," ngvglobal.com, 12 February 2013, http://www.ngvglobal. com/enoc-and-dubai-sign-mou-to-convert-flared-biogas-to-biomethane-fuel-0212; "California Energy Commission Funds Biomethane and CNG Fuel Projects," ngvglobal.com, 13 February 2013, http://www.ngvglobal.com/california-energy-commission-funds-biomethane-and-cng-fuel-projects-0213; "Valtra Plans Biomethane Dual-Fuel Tractor Production in 2013," ngvglobal. com, 15 September2012, http://www.ngvglobal.com/valtra-plans-biomethane-dual-fuel-tractor-production-in-2013-0915.
118 See, forexample, Dave Hurst, "Are E-Bicycle Sales Reducing Car Sales in Europe?" Forbes, 8 May 2013, http://www.forbes.com/sites/pikeresearch/2013/05/08/are-e-bicycle-sales-reducing-car-sales-in-europe/; IEA, Clean Energy Ministerial, Electric Vehicles Initiative, Global EV Outlook: Understanding the Electric Vehicle Landscape to 2020 (Paris: OECD/IEA, April 2013), http://cleanenergyministerial.org/Portals/2/pdfs/EVI_GEO_2013_FINAL_150dpi.pdf.
119 GIZ, prepared on behalf of Federal Ministryfor Economic Cooperation and Development, "Renewables in Rail Transport: Approaches and Examples," compiled by Nicolai Bader, GIZ, April 2014.
120 BYD, "Bogota Launches the Largest All-electric Taxi Fleet in South America," press release (Bogota: 3 September 2013), http://www.byd.com/news/news-172.html; Nino Marchetti, "Colombian Police Turn to Electric Motorcycles," EarthTechling. com, 1 July 2013, http://earthtechling.com/2013/07/colombian-police-turn-to-electric-motorcycles/.
121 In Norway, about 1,200 EVs are sold monthly, from S. Morlin-Yron, "Norway - electric vehicles lead the car market," The Ecologist, 4 February 2014, http://www.theecologist.org/News/news_round_up/2266537/norway_electric_vehicles_lead_the_car_market. html.
122 U.S. Department of Energy, Energy Efficiency and Renewable Energy, "Alternative Fuels Data Center," updated 30 December 2013, http://www.afdc.energy.gov/locator/stations/. More than 20% of these are in California.
123 Leidreiter, op. cit. note 21. Forexample, Dardesheim, Germany, produces more energy than it needs for power, heating, cooling, and mobility, and has started to integrate electric vehicles into its energy plan, from Leidreiter, Moss, and Groth, op. cit. note 109, p. 35.
124 "Vehicle" is defined as passengercars, lorries, and other road vehicles, and "fossil-fuel-independent vehicle fleet" as "road transport system whose vehicles are driven primarily by biofuels or electricity," from Swedish Government, "A Cohesive Swedish Climate and Energy Policy," Govt. Bill 2008/09:162, cited in Fossilfrihet påväg, Del 1 (Stockholm: 2013), Report no. SOU 2013: 84, http://www.regeringen.Se/content/1/c6/23/07/39/1591b3dd.pdf. Executive Summary in English is available at http://www.sou. gov.se/content/1/c6/21/33/36/aa2e5cb3.pdf.
125 Heather Allen, Transport Research Laboratory, United Kingdom, personal communication with REN21, 31 March 2014.
126 Sawyer, op. cit. note 44; Samuel Shen and Kazunori Takada, "Chinese Cities Open Up Green Car Markets as Government Battles Pollution," Reuters, 21 March 2014, http://planetark. org/wen/71258. F Tuffnerand M. Kintner-Meyer, Using Electric Vehicles to Meet Balancing Requirements Associated with Wind Power (Richland, WA: Pacific Northwest Laboratory, 2011), prepared for U.S. Department of Energy, http://energyenvironment. pnnl.gov/pdf/PNNL-20501_Renewables_lntegration_Report_Final_7_8_2011.pdf; "Innovative EV Charging System Includes Solar Power, Battery Energy Storage," Smart Grid News, 31 January 2013, http://www.smartgridnews.com/artman/publish/End_Use_Electric_Transportation/lnnovative-EV-charging-system-includes-solar-power-battery-storage-5477.html; Phil Carson, "The Business of V2G: Technology and Business Case Go Hand in Hand," Intelligent Utility Magazine, September/October 2012, http://www.htelligentutility.com/magazine/article/284831/business-v2g; J.A. Pegas Lopes et al., "Smart Charging Strategies for Electric Vehicles: Enhancing Grid Performance and Maximizing the Use of Variable Renewable Energy Resources," EVS24 International Battery, Hybrid and Fuel Cell Electric Vehicle Symposium, Stavanger, Norway, 13-16 May 2009, http://www.altomelbilen.dk/presentationer/Smart%20Grid%20Strategies.pdf.